The controversy over Volkswagen's diesel emissions scandal isn't limited to the US. In Europe, where diesel engines are far more popular, the issue is shining a harsh light on the NEDC emissions test.

As already known, the evaluation does a poor job of reflecting real-world production of NOx, and it appears a significant number of automakers are affected.

The Guardian in the UK has been reporting on real-world test results from a company called Emissions Analytics. After the latest round of checks, vehicles from Mercedes-Benz, Honda, Mazda and Mitsubishi were found to generate far more NOx than they should. The newspaper also published similar results for Renault, Nissan, Hyundai, Fiat, Volvo, Jeep, Citroën, VW, and Audi. On average, the figures are about four times over the limit of producing the pollutant.

Unlike VW and its defeat device, these automakers aren't actually breaking the rules. The vehicles perform up to the NEDC lab test for emissions, but those results simply aren't translated to the street. "The VW issue in the US was purely the trigger which threw light on a slightly different problem in the EU - widespread legal over-emissions," Nick Molden from Emissions Analytics said to The Guardian.

A big fight to decide the future of this issue appears to be on the horizon. Automakers claim that they can't meet the next round of tightening emissions regulations and are asking for compromises. Although, spokespeople for Mercedes and Honda told The Guardian that the brands would be in favor of the stricter rules. Meanwhile, some European governments began backtracking their support of diesels well before this scandal came to light. The added scrutiny certain hasn't helped the future of the oil-burner.